I just left a comment on the StorageRap blog about “stay-thin” features recently released by 3Par and it looks like this:
Hey Marc,
Well, you have the thinnest array of the world, i read some articles,documentation and obviously your blog about new features just released by 3Par and your company has done a good job on them (IMHO). above all i like the reclamation for Veritas Storage Foundation , it’s very good because the Veritas layer is often used in enterprises to manage storage, good shot!
3Par has joined (and probably now leads) the small group of vendors than can provision thin LUNs with the ability to stay thin: HDS, Compellent and now 3Par are the other members coming to my mind now.
Probably we are going to talk a lot about different implementations of this features in the near future, but, as Chris Evans (the Storage Architect) reminds us EMC will not be at this party! 
ciao,
Enrico
What is doing Compellent about Thin Provisioning?
Thin provisioning is one of the most interesting features being proposed by some storage vendors. The ability to provision thin LUNs permits to optimize the utilization of allocated storage by not preallocating unused space.
Compellent has his own implementation (called dynamic capacity) and it is one of the most important factor of their success. The whole storage center is “thin”, every feature is “thin”: LUNs, snapshots, replicas, and so on! Think thin!
Compellent has, at least, two important feature to list: Thin import and space reclamation.
Thin import is the ability to import directly (array to array) fat LUNs from Legacy storage volumes to the Compellent storage. You can migrate from old to new and from fat to thin with a single operation! Start thin!
Free space recovery operates with the Windows file system to identify and reclaim space no longer in use. In other SANs, after Windows files are deleted from a thin provisioned volume, the operating system will continue to report that the space is unavailable. Free Space Recovery automatically reclaims this space over time. Stay thin!
Please ask your storage vendor how thin he is!!!
ES
